It underlines just why the former NSA computer specialist Edward Snowden is so deserving of the status of whistleblower. He has revealed that what we journalists might have suspected about government surveillance to be true was indeed so.

The article tells how Snowden first tried to win the attention of Guardian journalist Glenn Greenwald by anonymously emailing him to say he had sensitive documents he wanted to share.

He followed that up with a step-by-step guide on how to encrypt communications, and then sent a link to an encryption video. Greenwald ignored the approaches.

In frustration, Snowden contacted documentary filmmaker Laura Poitras. And it was she who eventually got in touch with Greenwald, drawing the three of them together.

Maass asked Snowden, in an encrypted email exchange, what he thought about Greenwald's initial silence in response to his requests and instructions for encrypted communications. Snowden replied that he understood journalists were busy "and had assumed being taken seriously would be a challenge".

And then he added: "At the same time, this is 2013, and [he is] a journalist who regularly reported on the concentration and excess of state power. I was surprised to realise that there were people in news organisations who didn't recognise any unencrypted message sent over the internet is being delivered to every intelligence service in the world."

And that's a killer point, surely. We might have thought that our emails were not secure. But Snowden's leaks confirm that they were not, and are not. And he thought us naive for believing otherwise.

There is much more to appreciate in Maass's article in which Poitras emerges as a crucial figure in the leaking process.

She first met Greenwald in 2010, when she became interested in his work on WikiLeaks and was planning to make a documentary on surveillance. Before that, she had already been subjected to unwelcome attention from the US authorities.

After filming the effects of the invasion of Iraq on its citizens, she discovered in June 2006 that her tickets on domestic flights were marked "SSSS" – Secondary Security Screening Selection. It meant that she faced extra scrutiny at airports.

The article details several examples. In all, she was stopped for questioning on more than 40 occasions. Eventually, in April 2012, Greenwald – then writing for Salon.com – told of her tribulations in a piece headlined US filmmaker repeatedly detained at border.

That article piqued Snowden's interest too. That was why he first attempted to contact Greenwald and why, having been ignored, he then tried Poitras.

Once the links were made, Snowden began to provide documents to both of them. Then, in May this year, Snowden sent encrypted messages telling them to go to Hong Kong.

Greenwald flew to New York from Rio, and Poitras joined him for meetings with the editor of the Guardian's US edition. It was decided that they should be accompanied on their trip to Hong Kong with the veteran Guardian reporter, Ewen MacAskill.

What follow was a classic cloak-and-dagger operation. Maass picks up the story: "Snowden had instructed them that once they were in Hong Kong, they were to go at an appointed time to the Kowloon district and stand outside a restaurant that was in a mall connected to the Mira hotel.

There, they were to wait until they saw a man carrying a Rubik's Cube, then ask him when the restaurant would open. The man would answer their question, but then warn that the food was bad. When the man with the Rubik's Cube arrived, it was Edward Snowden."

They followed Snowden to his room. Poitras began filming and Greenwald began questioning. It went on for a week during which the first article "NSA collecting phone records of millions of Verizon customers" was published on 6 June by the Guardian.

Poitras told Maass: "We were all surprised at how much attention it was getting … we could see on TV that it was taking off."

After Poitras made a video of Snowden, duly posted on 9 June, he checked out of his hotel and went into hiding. A week later, Poitras flew to Berlin, "where she could edit her documentary without worrying that the FBI would show up with a search warrant."

And two weeks after that she flew to Brazil. It was there, in a Rio de Janeiro hotel, that Maass met her along with Greenwald, where they were working with MacAskill and another Guardian journalist, James Ball.

It was several days before they all discovered that Snowden had arrived at Moscow airport.

In Maass's encrypted conversation with Snowden the whistleblower explained why he went to Poitras with his secrets: "Laura and Glenn are among the few who reported fearlessly on controversial topics throughout this period, even in the face of withering personal criticism, [which] resulted in Laura specifically becoming targeted by the very programmes involved in the recent disclosures.

She had demonstrated the courage, personal experience and skill needed to handle what is probably the most dangerous assignment any journalist can be given — reporting on the secret misdeeds of the most powerful government in the world — making her an obvious choice."

Snowden's revelations, unsurprisingly, are now the centre of Poitras's surveillance documentary. Meanwhile, she is also assessing her legal vulnerability.

Poitras and Greenwald are not facing charges, at least not yet. They do not plan to stay away from the US forever, but have no immediate plans to return.

With at least one member of Congress having accused them of treason, they are also aware of the Obama administration's pursuit of both leakers and the journalists who receive leaks.